and most precipitation falls during winter. This aridity is caused by the rain shadow effect of the Subandean Ranges, which block moisture from the Atlantic Ocean. Eruption history One andesitic lava flow on the northwestern slope of Incahuasi has yielded two ages, one of 1.15 ± 0.5 million years ago and another of 710,000 ± 80,000 years ago. Based on their preservations, the lava flows appear to be of roughly comparable ages. Additional ages were obtained on the main edifice, 1.57 ± 0.1 million years ago, 1.14 ± 0.37 million years ago, and 1.00 ± 0.13 million years ago. Parasitic cones were active over 500,000 years ago. These include the lava dome and lava flow fields (760,000 ± 90,000 and 740,000 ± 50,000 years ago, respectively) and a lava flow from the pyroclastic cones, which has been dated to 350,000 ± 30,000 years ago. Volcanic activity at Incahuasi may have continued into the Holocene, considering the young appearance of its eruption products such as lava flows in the summit region and on the southern slopes; the old ages obtained by radiometric dating indicate an extinct volcano, although activity at Andean volcanoes is known to occur with long rest phases between eruptions (reaching one million years). There are reports of fumarolic activity. The volcano is considered a potential geological hazard to Argentina and Chile, where the SERNAGEOMIN hazard maps identify it as a potential threat. The remoteness of the volcano means that future eruptions are unlikely to impact populated areas, however, other than . It was rated 27th out of 38 Argentine-Chilean volcanoes in dangerousness. Climbing history The mountain was first climbed by Inca people. In 1912, Walter Penck climbed the mountain. Legend has it that a railway engineer named Edward Flint ascended the mountain between 1854 and 1859. Archaeology In 1913, an Inca ceremonial structure was found on the summit of Incahuasi. Another archaeological site, "Fiambalá-1", lies at its foot. Other Inca archaeological sites in the region appear to have had functions correlated to that of the Incahuasi site. See also List of volcanoes in Chile List of volcanoes in Argentina List of Ultras of South America Ojos del Salado Nevado Tres Cruces Cerro El Muerto References Sources External links Incahuasi "Cerro de Incahuasi, Argentina/Chile" on Peakbagger Volcanoes of Atacama Region Mountains of Argentina Mountains of Chile Volcanoes of Catamarca Province Polygenetic volcanoes Argentina–Chile border International mountains of South America